4516c36436e6187e053d74c5766ea020036a2218
[linux-2.6.git] / drivers / usb / wusbcore / security.c
1 /*
2  * Wireless USB Host Controller
3  * Security support: encryption enablement, etc
4  *
5  * Copyright (C) 2006 Intel Corporation
6  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License version
10  * 2 as published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20  * 02110-1301, USA.
21  *
22  *
23  * FIXME: docs
24  */
25 #include <linux/types.h>
26 #include <linux/usb/ch9.h>
27 #include <linux/random.h>
28 #include "wusbhc.h"
29
30 static void wusbhc_set_gtk_callback(struct urb *urb);
31 static void wusbhc_gtk_rekey_done_work(struct work_struct *work);
32
33 int wusbhc_sec_create(struct wusbhc *wusbhc)
34 {
35         wusbhc->gtk.descr.bLength = sizeof(wusbhc->gtk.descr) + sizeof(wusbhc->gtk.data);
36         wusbhc->gtk.descr.bDescriptorType = USB_DT_KEY;
37         wusbhc->gtk.descr.bReserved = 0;
38
39         wusbhc->gtk_index = wusb_key_index(0, WUSB_KEY_INDEX_TYPE_GTK,
40                                            WUSB_KEY_INDEX_ORIGINATOR_HOST);
41
42         INIT_WORK(&wusbhc->gtk_rekey_done_work, wusbhc_gtk_rekey_done_work);
43
44         return 0;
45 }
46
47
48 /* Called when the HC is destroyed */
49 void wusbhc_sec_destroy(struct wusbhc *wusbhc)
50 {
51 }
52
53
54 /**
55  * wusbhc_next_tkid - generate a new, currently unused, TKID
56  * @wusbhc:   the WUSB host controller
57  * @wusb_dev: the device whose PTK the TKID is for
58  *            (or NULL for a TKID for a GTK)
59  *
60  * The generated TKID consist of two parts: the device's authenicated
61  * address (or 0 or a GTK); and an incrementing number.  This ensures
62  * that TKIDs cannot be shared between devices and by the time the
63  * incrementing number wraps around the older TKIDs will no longer be
64  * in use (a maximum of two keys may be active at any one time).
65  */
66 static u32 wusbhc_next_tkid(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
67 {
68         u32 *tkid;
69         u32 addr;
70
71         if (wusb_dev == NULL) {
72                 tkid = &wusbhc->gtk_tkid;
73                 addr = 0;
74         } else {
75                 tkid = &wusb_port_by_idx(wusbhc, wusb_dev->port_idx)->ptk_tkid;
76                 addr = wusb_dev->addr & 0x7f;
77         }
78
79         *tkid = (addr << 8) | ((*tkid + 1) & 0xff);
80
81         return *tkid;
82 }
83
84 static void wusbhc_generate_gtk(struct wusbhc *wusbhc)
85 {
86         const size_t key_size = sizeof(wusbhc->gtk.data);
87         u32 tkid;
88
89         tkid = wusbhc_next_tkid(wusbhc, NULL);
90
91         wusbhc->gtk.descr.tTKID[0] = (tkid >>  0) & 0xff;
92         wusbhc->gtk.descr.tTKID[1] = (tkid >>  8) & 0xff;
93         wusbhc->gtk.descr.tTKID[2] = (tkid >> 16) & 0xff;
94
95         get_random_bytes(wusbhc->gtk.descr.bKeyData, key_size);
96 }
97
98 /**
99  * wusbhc_sec_start - start the security management process
100  * @wusbhc: the WUSB host controller
101  *
102  * Generate and set an initial GTK on the host controller.
103  *
104  * Called when the HC is started.
105  */
106 int wusbhc_sec_start(struct wusbhc *wusbhc)
107 {
108         const size_t key_size = sizeof(wusbhc->gtk.data);
109         int result;
110
111         wusbhc_generate_gtk(wusbhc);
112
113         result = wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid,
114                                  &wusbhc->gtk.descr.bKeyData, key_size);
115         if (result < 0)
116                 dev_err(wusbhc->dev, "cannot set GTK for the host: %d\n",
117                         result);
118
119         return result;
120 }
121
122 /**
123  * wusbhc_sec_stop - stop the security management process
124  * @wusbhc: the WUSB host controller
125  *
126  * Wait for any pending GTK rekeys to stop.
127  */
128 void wusbhc_sec_stop(struct wusbhc *wusbhc)
129 {
130         cancel_work_sync(&wusbhc->gtk_rekey_done_work);
131 }
132
133
134 /** @returns encryption type name */
135 const char *wusb_et_name(u8 x)
136 {
137         switch (x) {
138         case USB_ENC_TYPE_UNSECURE:     return "unsecure";
139         case USB_ENC_TYPE_WIRED:        return "wired";
140         case USB_ENC_TYPE_CCM_1:        return "CCM-1";
141         case USB_ENC_TYPE_RSA_1:        return "RSA-1";
142         default:                        return "unknown";
143         }
144 }
145 EXPORT_SYMBOL_GPL(wusb_et_name);
146
147 /*
148  * Set the device encryption method
149  *
150  * We tell the device which encryption method to use; we do this when
151  * setting up the device's security.
152  */
153 static int wusb_dev_set_encryption(struct usb_device *usb_dev, int value)
154 {
155         int result;
156         struct device *dev = &usb_dev->dev;
157         struct wusb_dev *wusb_dev = usb_dev->wusb_dev;
158
159         if (value) {
160                 value = wusb_dev->ccm1_etd.bEncryptionValue;
161         } else {
162                 /* FIXME: should be wusb_dev->etd[UNSECURE].bEncryptionValue */
163                 value = 0;
164         }
165         /* Set device's */
166         result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
167                         USB_REQ_SET_ENCRYPTION,
168                         USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
169                         value, 0, NULL, 0, 1000 /* FIXME: arbitrary */);
170         if (result < 0)
171                 dev_err(dev, "Can't set device's WUSB encryption to "
172                         "%s (value %d): %d\n",
173                         wusb_et_name(wusb_dev->ccm1_etd.bEncryptionType),
174                         wusb_dev->ccm1_etd.bEncryptionValue,  result);
175         return result;
176 }
177
178 /*
179  * Set the GTK to be used by a device.
180  *
181  * The device must be authenticated.
182  */
183 static int wusb_dev_set_gtk(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
184 {
185         struct usb_device *usb_dev = wusb_dev->usb_dev;
186
187         return usb_control_msg(
188                 usb_dev, usb_sndctrlpipe(usb_dev, 0),
189                 USB_REQ_SET_DESCRIPTOR,
190                 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
191                 USB_DT_KEY << 8 | wusbhc->gtk_index, 0,
192                 &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
193                 1000);
194 }
195
196
197 /* FIXME: prototype for adding security */
198 int wusb_dev_sec_add(struct wusbhc *wusbhc,
199                      struct usb_device *usb_dev, struct wusb_dev *wusb_dev)
200 {
201         int result, bytes, secd_size;
202         struct device *dev = &usb_dev->dev;
203         struct usb_security_descriptor *secd;
204         const struct usb_encryption_descriptor *etd, *ccm1_etd = NULL;
205         const void *itr, *top;
206         char buf[64];
207
208         secd = kmalloc(sizeof(struct usb_security_descriptor), GFP_KERNEL);
209         if (secd == NULL) {
210                 result = -ENOMEM;
211                 goto out;
212         }
213
214         result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
215                                     0, secd, sizeof(struct usb_security_descriptor));
216         if (result < sizeof(secd)) {
217                 dev_err(dev, "Can't read security descriptor or "
218                         "not enough data: %d\n", result);
219                 goto out;
220         }
221         secd_size = le16_to_cpu(secd->wTotalLength);
222         secd = krealloc(secd, secd_size, GFP_KERNEL);
223         if (secd == NULL) {
224                 dev_err(dev, "Can't allocate space for security descriptors\n");
225                 goto out;
226         }
227         result = usb_get_descriptor(usb_dev, USB_DT_SECURITY,
228                                     0, secd, secd_size);
229         if (result < secd_size) {
230                 dev_err(dev, "Can't read security descriptor or "
231                         "not enough data: %d\n", result);
232                 goto out;
233         }
234         bytes = 0;
235         itr = &secd[1];
236         top = (void *)secd + result;
237         while (itr < top) {
238                 etd = itr;
239                 if (top - itr < sizeof(*etd)) {
240                         dev_err(dev, "BUG: bad device security descriptor; "
241                                 "not enough data (%zu vs %zu bytes left)\n",
242                                 top - itr, sizeof(*etd));
243                         break;
244                 }
245                 if (etd->bLength < sizeof(*etd)) {
246                         dev_err(dev, "BUG: bad device encryption descriptor; "
247                                 "descriptor is too short "
248                                 "(%u vs %zu needed)\n",
249                                 etd->bLength, sizeof(*etd));
250                         break;
251                 }
252                 itr += etd->bLength;
253                 bytes += snprintf(buf + bytes, sizeof(buf) - bytes,
254                                   "%s (0x%02x/%02x) ",
255                                   wusb_et_name(etd->bEncryptionType),
256                                   etd->bEncryptionValue, etd->bAuthKeyIndex);
257                 if (etd->bEncryptionType == USB_ENC_TYPE_CCM_1)
258                         ccm1_etd = etd;
259         }
260         /* This code only supports CCM1 as of now. */
261         /* FIXME: user has to choose which sec mode to use?
262          * In theory we want CCM */
263         if (ccm1_etd == NULL) {
264                 dev_err(dev, "WUSB device doesn't support CCM1 encryption, "
265                         "can't use!\n");
266                 result = -EINVAL;
267                 goto out;
268         }
269         wusb_dev->ccm1_etd = *ccm1_etd;
270         dev_dbg(dev, "supported encryption: %s; using %s (0x%02x/%02x)\n",
271                 buf, wusb_et_name(ccm1_etd->bEncryptionType),
272                 ccm1_etd->bEncryptionValue, ccm1_etd->bAuthKeyIndex);
273         result = 0;
274 out:
275         kfree(secd);
276         return result;
277 }
278
279 void wusb_dev_sec_rm(struct wusb_dev *wusb_dev)
280 {
281         /* Nothing so far */
282 }
283
284 /**
285  * Update the address of an unauthenticated WUSB device
286  *
287  * Once we have successfully authenticated, we take it to addr0 state
288  * and then to a normal address.
289  *
290  * Before the device's address (as known by it) was usb_dev->devnum |
291  * 0x80 (unauthenticated address). With this we update it to usb_dev->devnum.
292  */
293 int wusb_dev_update_address(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev)
294 {
295         int result = -ENOMEM;
296         struct usb_device *usb_dev = wusb_dev->usb_dev;
297         struct device *dev = &usb_dev->dev;
298         u8 new_address = wusb_dev->addr & 0x7F;
299
300         /* Set address 0 */
301         result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
302                                  USB_REQ_SET_ADDRESS, 0,
303                                  0, 0, NULL, 0, 1000 /* FIXME: arbitrary */);
304         if (result < 0) {
305                 dev_err(dev, "auth failed: can't set address 0: %d\n",
306                         result);
307                 goto error_addr0;
308         }
309         result = wusb_set_dev_addr(wusbhc, wusb_dev, 0);
310         if (result < 0)
311                 goto error_addr0;
312         usb_set_device_state(usb_dev, USB_STATE_DEFAULT);
313         usb_ep0_reinit(usb_dev);
314
315         /* Set new (authenticated) address. */
316         result = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
317                                  USB_REQ_SET_ADDRESS, 0,
318                                  new_address, 0, NULL, 0,
319                                  1000 /* FIXME: arbitrary */);
320         if (result < 0) {
321                 dev_err(dev, "auth failed: can't set address %u: %d\n",
322                         new_address, result);
323                 goto error_addr;
324         }
325         result = wusb_set_dev_addr(wusbhc, wusb_dev, new_address);
326         if (result < 0)
327                 goto error_addr;
328         usb_set_device_state(usb_dev, USB_STATE_ADDRESS);
329         usb_ep0_reinit(usb_dev);
330         usb_dev->authenticated = 1;
331 error_addr:
332 error_addr0:
333         return result;
334 }
335
336 /*
337  *
338  *
339  */
340 /* FIXME: split and cleanup */
341 int wusb_dev_4way_handshake(struct wusbhc *wusbhc, struct wusb_dev *wusb_dev,
342                             struct wusb_ckhdid *ck)
343 {
344         int result = -ENOMEM;
345         struct usb_device *usb_dev = wusb_dev->usb_dev;
346         struct device *dev = &usb_dev->dev;
347         u32 tkid;
348         __le32 tkid_le;
349         struct usb_handshake *hs;
350         struct aes_ccm_nonce ccm_n;
351         u8 mic[8];
352         struct wusb_keydvt_in keydvt_in;
353         struct wusb_keydvt_out keydvt_out;
354
355         hs = kzalloc(3*sizeof(hs[0]), GFP_KERNEL);
356         if (hs == NULL) {
357                 dev_err(dev, "can't allocate handshake data\n");
358                 goto error_kzalloc;
359         }
360
361         /* We need to turn encryption before beginning the 4way
362          * hshake (WUSB1.0[.3.2.2]) */
363         result = wusb_dev_set_encryption(usb_dev, 1);
364         if (result < 0)
365                 goto error_dev_set_encryption;
366
367         tkid = wusbhc_next_tkid(wusbhc, wusb_dev);
368         tkid_le = cpu_to_le32(tkid);
369
370         hs[0].bMessageNumber = 1;
371         hs[0].bStatus = 0;
372         memcpy(hs[0].tTKID, &tkid_le, sizeof(hs[0].tTKID));
373         hs[0].bReserved = 0;
374         memcpy(hs[0].CDID, &wusb_dev->cdid, sizeof(hs[0].CDID));
375         get_random_bytes(&hs[0].nonce, sizeof(hs[0].nonce));
376         memset(hs[0].MIC, 0, sizeof(hs[0].MIC));        /* Per WUSB1.0[T7-22] */
377
378         result = usb_control_msg(
379                 usb_dev, usb_sndctrlpipe(usb_dev, 0),
380                 USB_REQ_SET_HANDSHAKE,
381                 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
382                 1, 0, &hs[0], sizeof(hs[0]), 1000 /* FIXME: arbitrary */);
383         if (result < 0) {
384                 dev_err(dev, "Handshake1: request failed: %d\n", result);
385                 goto error_hs1;
386         }
387
388         /* Handshake 2, from the device -- need to verify fields */
389         result = usb_control_msg(
390                 usb_dev, usb_rcvctrlpipe(usb_dev, 0),
391                 USB_REQ_GET_HANDSHAKE,
392                 USB_DIR_IN | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
393                 2, 0, &hs[1], sizeof(hs[1]), 1000 /* FIXME: arbitrary */);
394         if (result < 0) {
395                 dev_err(dev, "Handshake2: request failed: %d\n", result);
396                 goto error_hs2;
397         }
398
399         result = -EINVAL;
400         if (hs[1].bMessageNumber != 2) {
401                 dev_err(dev, "Handshake2 failed: bad message number %u\n",
402                         hs[1].bMessageNumber);
403                 goto error_hs2;
404         }
405         if (hs[1].bStatus != 0) {
406                 dev_err(dev, "Handshake2 failed: bad status %u\n",
407                         hs[1].bStatus);
408                 goto error_hs2;
409         }
410         if (memcmp(hs[0].tTKID, hs[1].tTKID, sizeof(hs[0].tTKID))) {
411                 dev_err(dev, "Handshake2 failed: TKID mismatch "
412                         "(#1 0x%02x%02x%02x vs #2 0x%02x%02x%02x)\n",
413                         hs[0].tTKID[0], hs[0].tTKID[1], hs[0].tTKID[2],
414                         hs[1].tTKID[0], hs[1].tTKID[1], hs[1].tTKID[2]);
415                 goto error_hs2;
416         }
417         if (memcmp(hs[0].CDID, hs[1].CDID, sizeof(hs[0].CDID))) {
418                 dev_err(dev, "Handshake2 failed: CDID mismatch\n");
419                 goto error_hs2;
420         }
421
422         /* Setup the CCM nonce */
423         memset(&ccm_n.sfn, 0, sizeof(ccm_n.sfn));       /* Per WUSB1.0[6.5.2] */
424         memcpy(ccm_n.tkid, &tkid_le, sizeof(ccm_n.tkid));
425         ccm_n.src_addr = wusbhc->uwb_rc->uwb_dev.dev_addr;
426         ccm_n.dest_addr.data[0] = wusb_dev->addr;
427         ccm_n.dest_addr.data[1] = 0;
428
429         /* Derive the KCK and PTK from CK, the CCM, H and D nonces */
430         memcpy(keydvt_in.hnonce, hs[0].nonce, sizeof(keydvt_in.hnonce));
431         memcpy(keydvt_in.dnonce, hs[1].nonce, sizeof(keydvt_in.dnonce));
432         result = wusb_key_derive(&keydvt_out, ck->data, &ccm_n, &keydvt_in);
433         if (result < 0) {
434                 dev_err(dev, "Handshake2 failed: cannot derive keys: %d\n",
435                         result);
436                 goto error_hs2;
437         }
438
439         /* Compute MIC and verify it */
440         result = wusb_oob_mic(mic, keydvt_out.kck, &ccm_n, &hs[1]);
441         if (result < 0) {
442                 dev_err(dev, "Handshake2 failed: cannot compute MIC: %d\n",
443                         result);
444                 goto error_hs2;
445         }
446
447         if (memcmp(hs[1].MIC, mic, sizeof(hs[1].MIC))) {
448                 dev_err(dev, "Handshake2 failed: MIC mismatch\n");
449                 goto error_hs2;
450         }
451
452         /* Send Handshake3 */
453         hs[2].bMessageNumber = 3;
454         hs[2].bStatus = 0;
455         memcpy(hs[2].tTKID, &tkid_le, sizeof(hs[2].tTKID));
456         hs[2].bReserved = 0;
457         memcpy(hs[2].CDID, &wusb_dev->cdid, sizeof(hs[2].CDID));
458         memcpy(hs[2].nonce, hs[0].nonce, sizeof(hs[2].nonce));
459         result = wusb_oob_mic(hs[2].MIC, keydvt_out.kck, &ccm_n, &hs[2]);
460         if (result < 0) {
461                 dev_err(dev, "Handshake3 failed: cannot compute MIC: %d\n",
462                         result);
463                 goto error_hs2;
464         }
465
466         result = usb_control_msg(
467                 usb_dev, usb_sndctrlpipe(usb_dev, 0),
468                 USB_REQ_SET_HANDSHAKE,
469                 USB_DIR_OUT | USB_TYPE_STANDARD | USB_RECIP_DEVICE,
470                 3, 0, &hs[2], sizeof(hs[2]), 1000 /* FIXME: arbitrary */);
471         if (result < 0) {
472                 dev_err(dev, "Handshake3: request failed: %d\n", result);
473                 goto error_hs3;
474         }
475
476         result = wusbhc->set_ptk(wusbhc, wusb_dev->port_idx, tkid,
477                                  keydvt_out.ptk, sizeof(keydvt_out.ptk));
478         if (result < 0)
479                 goto error_wusbhc_set_ptk;
480
481         result = wusb_dev_set_gtk(wusbhc, wusb_dev);
482         if (result < 0) {
483                 dev_err(dev, "Set GTK for device: request failed: %d\n",
484                         result);
485                 goto error_wusbhc_set_gtk;
486         }
487
488         /* Update the device's address from unauth to auth */
489         if (usb_dev->authenticated == 0) {
490                 result = wusb_dev_update_address(wusbhc, wusb_dev);
491                 if (result < 0)
492                         goto error_dev_update_address;
493         }
494         result = 0;
495         dev_info(dev, "device authenticated\n");
496
497 error_dev_update_address:
498 error_wusbhc_set_gtk:
499 error_wusbhc_set_ptk:
500 error_hs3:
501 error_hs2:
502 error_hs1:
503         memset(hs, 0, 3*sizeof(hs[0]));
504         memset(&keydvt_out, 0, sizeof(keydvt_out));
505         memset(&keydvt_in, 0, sizeof(keydvt_in));
506         memset(&ccm_n, 0, sizeof(ccm_n));
507         memset(mic, 0, sizeof(mic));
508         if (result < 0)
509                 wusb_dev_set_encryption(usb_dev, 0);
510 error_dev_set_encryption:
511         kfree(hs);
512 error_kzalloc:
513         return result;
514 }
515
516 /*
517  * Once all connected and authenticated devices have received the new
518  * GTK, switch the host to using it.
519  */
520 static void wusbhc_gtk_rekey_done_work(struct work_struct *work)
521 {
522         struct wusbhc *wusbhc = container_of(work, struct wusbhc, gtk_rekey_done_work);
523         size_t key_size = sizeof(wusbhc->gtk.data);
524
525         mutex_lock(&wusbhc->mutex);
526
527         if (--wusbhc->pending_set_gtks == 0)
528                 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);
529
530         mutex_unlock(&wusbhc->mutex);
531 }
532
533 static void wusbhc_set_gtk_callback(struct urb *urb)
534 {
535         struct wusbhc *wusbhc = urb->context;
536
537         queue_work(wusbd, &wusbhc->gtk_rekey_done_work);
538 }
539
540 /**
541  * wusbhc_gtk_rekey - generate and distribute a new GTK
542  * @wusbhc: the WUSB host controller
543  *
544  * Generate a new GTK and distribute it to all connected and
545  * authenticated devices.  When all devices have the new GTK, the host
546  * starts using it.
547  *
548  * This must be called after every device disconnect (see [WUSB]
549  * section 6.2.11.2).
550  */
551 void wusbhc_gtk_rekey(struct wusbhc *wusbhc)
552 {
553         static const size_t key_size = sizeof(wusbhc->gtk.data);
554         int p;
555
556         wusbhc_generate_gtk(wusbhc);
557
558         for (p = 0; p < wusbhc->ports_max; p++) {
559                 struct wusb_dev *wusb_dev;
560
561                 wusb_dev = wusbhc->port[p].wusb_dev;
562                 if (!wusb_dev || !wusb_dev->usb_dev || !wusb_dev->usb_dev->authenticated)
563                         continue;
564
565                 usb_fill_control_urb(wusb_dev->set_gtk_urb, wusb_dev->usb_dev,
566                                      usb_sndctrlpipe(wusb_dev->usb_dev, 0),
567                                      (void *)wusb_dev->set_gtk_req,
568                                      &wusbhc->gtk.descr, wusbhc->gtk.descr.bLength,
569                                      wusbhc_set_gtk_callback, wusbhc);
570                 if (usb_submit_urb(wusb_dev->set_gtk_urb, GFP_KERNEL) == 0)
571                         wusbhc->pending_set_gtks++;
572         }
573         if (wusbhc->pending_set_gtks == 0)
574                 wusbhc->set_gtk(wusbhc, wusbhc->gtk_tkid, &wusbhc->gtk.descr.bKeyData, key_size);
575 }